Tetrapulmonata

Taxobox
name = Tetrapulmonata


image_caption =
image_width = 250px
status =
extinct =
regnum = Animalia
phylum = Arthropoda
classis = Arachnida
unranked_ordo = Tetrapulmonata (Thelyphonida, Schizomida, Amblypygi and Araneae).

Tetrapulmonata Shultz, 1990 is a non-ranked supra-ordinal group of arachnids. It is composed of Thelyphonida, Schizomida, Amblypygi and Araneae.

Etymology

It receives its name from the presence of paired book lungs occupying the second and third opisthosomal segments, although the posterior pair is absent in Schizomida. Previous synonyms of this lineage are rejected; Caulogastra (Pocock, 1983) refers to pedicel, which is symplesiomorphic for the lineage and convergent with Solifugae, and Arachnidea (van der Hammen, 1977) is easily confused with Arachnida.

Types

Other synapomorphies of Tetrapulmonata include a large postcerebral pharynx (reduced in Uropygi), prossomal endosternite with four segmental components, subchelate chelicerae, a complex coxotrochanteral joint in the walking legs, a pretarsal depressor muscle arising in the patella (convergent with Dromopoda, lost in Amblypygi), a pedicel formed, in part, by ventral elements of the second opisthomal segment and a spermatozoan axoneme a 9+3 microtubule arrangement (Schultz, 1990).

References

* (1990): Evolutionary morphology and phylogeny of Arachnida. "Cladistics" 6: 1-38.